Electrode array having concentric windowed cylinder electrodes and methods of making the same

ABSTRACT

A device for brain stimulation includes a lead body having a distal end section and at least one inner conductive cylinder with at least one inner window cut out from the inner cylinder. The inner cylinder is disposed at the distal end section of the lead body. The device also includes an outer conductive cylinder with at least one outer window cut out from the outer cylinder. The outer cylinder is secured to and disposed concentric to the inner cylinder with a portion of each of the at least one inner cylinder aligned with the at least one outer window of the outer cylinder. The device further includes an insulator configured and arranged to electrically insulate each of the at least one inner cylinder and the outer cylinder.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/945,623 filed Nov. 12, 2010, which claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Patent Application Ser. No. 61/265,229 filedon Nov. 30, 2009, all of which are incorporated herein by reference.

FIELD

The invention is directed to devices and methods for brain stimulationincluding deep brain stimulation. In addition, the invention is directedto devices and method for brain stimulation using a lead havingconcentric windowed cylinder electrodes.

BACKGROUND

Deep brain stimulation can be useful for treating a variety ofconditions including, for example, Parkinson's disease, dystonia,essential tremor, chronic pain, Huntington's Disease, levodopa-induceddyskinesias and rigidity, bradykinesia, epilepsy and seizures, eatingdisorders, and mood disorders. Typically, a lead with a stimulatingelectrode at or near a tip of the lead provides the stimulation totarget neurons in the brain. Magnetic resonance imaging (MRI) orcomputerized tomography (CT) scans can provide a starting point fordetermining where the stimulating electrode should be positioned toprovide the desired stimulus to the target neurons.

Upon insertion, current is introduced along the length of the lead tostimulate target neurons in the brain. This stimulation is provided byelectrodes, typically in the form of rings, disposed on the lead. Thecurrent projects from each electrode similarly and in all directions atany given length along the axis of the lead. Because of the shape of theelectrodes, radial selectivity of the current is minimal. This resultsin the unwanted stimulation of neighboring neural tissue, undesired sideeffects and an increased duration of time for the proper therapeuticeffect to be obtained.

In the field of deep brain stimulation, radially segmented electrodearrays (RSEA) have been developed to provide superior radial selectivityof current. Radially segmented electrode arrays are useful for deepbrain stimulation because the target structures in the deep brain areoften not symmetric about the axis of the distal electrode array. Insome cases, a target may be located on one side of a plane runningthrough the axis of the lead. In other cases, a target may be located ata plane that is offset at some angle from the axis of the lead. Thus,radially segmented electrode arrays may be useful for selectivelysimulating tissue. These radially segmented arrays may be made usingconcentric windowed cylinder electrodes.

BRIEF SUMMARY

In some embodiments, a device for brain stimulation includes a lead bodyhaving a distal end section and at least one inner conductive cylinderwith at least one inner window cut out from the inner cylinder. Theinner cylinder is disposed at the distal end section of the lead body.The device also includes an outer conductive cylinder with at least oneouter window cut out from the outer cylinder. The outer cylinder issecured to and disposed concentric to the inner cylinder with a portionof each of the at least one inner cylinder aligned with the at least oneouter window of the outer cylinder. The device further includes aninsulator configured and arranged to electrically insulate each of theat least one inner cylinder and the outer cylinder.

In another embodiment, a device for brain stimulation includes a leadhaving a longitudinal surface and a distal end. The lead includes aplurality of cylinder assemblies disposed along the longitudinal surfaceof the lead body near the distal end of the lead. Each of the pluralityof cylinder assemblies includes at least one inner conductive cylinderhaving at least one inner window and a concentric outer conductivecylinder having at least one outer window.

In yet another embodiment, a method of manufacturing a device for brainstimulation includes forming a lead body having a distal end section. Atleast one inner conductive cylinder is introduced about thecircumference of the lead body at the distal end section, the at leastone inner cylinder having at least one inner window. An outer conductivecylinder is secured around the at least one inner cylinder, the outercylinder having at least one outer window. Each of the at least oneinner cylinder and the outer cylinder is electrically insulated fromeach other using an insulator.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1A is a schematic perspective view of one embodiment of a portionof a lead having a plurality of segmented electrodes and a ringelectrode, according to the invention;

FIG. 1B is a schematic perspective view of another embodiment of a leadhaving a plurality of segmented electrodes arranged in staggeredorientation and a ring electrode, according to the invention;

FIG. 2 is a schematic diagram of radial current steering along variouselectrode levels along the length of a lead, according to the invention;

FIG. 3A is a schematic perspective view of one embodiment of an innercylinder, according to the invention;

FIG. 3B is a schematic perspective view of the inner cylinder of FIG. 3Aafter formation of a window, according to the invention;

FIG. 4A is a schematic perspective view of one embodiment of an outercylinder, according to the invention;

FIG. 4B is a schematic perspective view of the outer cylinder of FIG. 4Aafter formation of a window, according to the invention;

FIG. 5 is a schematic cross-sectional view of one embodiment of acylinder assembly having an inner cylinder, an outer cylinder and aninsulator, according to the invention;

FIG. 6 is a schematic perspective view of an inner cylinder disposedwithin the outer cylinder, according to the invention;

FIG. 7 is a schematic cross-sectional view of one embodiment of acylinder assembly showing the location of the inner window and the outerwindow, according to the invention;

FIG. 8 is a schematic perspective view of a cylinder assembly coupled toa plurality of conductors, according to the invention;

FIG. 9 is a schematic perspective view of a cylinder assembly having anelevating plate and coupled to a plurality of conductors, according tothe invention;

FIG. 10A is a schematic perspective view of one embodiment of a portionof a lead having a plurality of cylinder assemblies and spacers,according to the invention;

FIG. 10B is a schematic perspective view of another embodiment of aportion of a lead having a plurality of cylinder assemblies arranged ina staggered orientation, according to the invention;

FIG. 11 is a schematic cross-sectional view of one embodiment of acylinder assembly having two inner cylinders and one outer cylinder,according to the invention; and

FIG. 12 is a schematic side view of one embodiment of a device for brainstimulation, according to the invention.

DETAILED DESCRIPTION

The present invention is directed to the area of devices and methods forbrain stimulation including deep brain stimulation. In addition, theinvention is directed to devices and method for brain stimulation usinga lead having a plurality of concentric windowed cylinders.

A lead for deep brain stimulation may include stimulation electrodes,recording electrodes, or a combination of both. A practitioner maydetermine the position of the target neurons using the recordingelectrode(s) and then position the stimulation electrode(s) accordinglywithout removal of a recording lead and insertion of a stimulation lead.In some embodiments, the same electrodes can be used for both recordingand stimulation. In some embodiments, separate leads can be used; onewith recording electrodes which identify target neurons, and a secondlead with stimulation electrodes that replaces the first after targetneuron identification. A lead may include recording electrodes spacedaround the circumference of the lead to more precisely determine theposition of the target neurons. In at least some embodiments, the leadis rotatable so that the stimulation electrodes can be aligned with thetarget neurons after the neurons have been located using the recordingelectrodes.

Deep brain stimulation devices and leads are described in the art. See,for instance, U.S. Pat. 7,809,446 (“Devices and Methods For BrainStimulation”), and co-pending patent application U.S. Patent ApplicationPublication No. 2010-0076535 A1 (“Leads With Non-Circular-Shaped DistalEnds For Brain Stimulation Systems and Methods of Making and Using”).Each of these references is incorporated herein by reference in itsrespective entirety.

FIG. 12 illustrates one embodiment of a device 1000 for brainstimulation. The device includes a lead 1010, segmented electrodes 1020,a connector 1040 for connection of the electrodes to a control unit, anda stylet 1060 for assisting in insertion and positioning of the lead inthe patient's brain. The stylet 1060 can be made of a rigid material.Examples of suitable materials include tungsten, stainless steel, orplastic. The stylet 1060 may have a handle 1070 to assist insertion intothe lead, as well as rotation of the stylet and lead. The connector 1040fits over the proximal end of the lead 1010, preferably after removal ofthe stylet 1060.

In one example of operation, access to the desired position in the braincan be accomplished by drilling a hole in the patient's skull or craniumwith a cranial drill (commonly referred to as a burr), and coagulatingand incising the dura mater, or brain covering. The lead 1010 can beinserted into the cranium and brain tissue with the assistance of thestylet 1060. The lead can be guided to the target location within thebrain using, for example, a stereotactic frame and a microdrive motorsystem. In some embodiments, the microdrive motor system can be fully orpartially automatic. The microdrive motor system may be configured toperform one or more the following actions (alone or in combination):rotate the lead, insert the lead, or retract the lead. In someembodiments, measurement devices coupled to the muscles or other tissuesstimulated by the target neurons or a unit responsive to the patient orclinician can be coupled to the control unit or microdrive motor system.The measurement device, user, or clinician can indicate a response bythe target muscles or other tissues to the stimulation or recordingelectrode(s) to further identify the target neurons and facilitatepositioning of the stimulation electrode(s). For example, if the targetneurons are directed to a muscle experiencing tremors, a measurementdevice can be used to observe the muscle and indicate changes in tremorfrequency or amplitude in response to stimulation of neurons.Alternatively, the patient or clinician may observe the muscle andprovide feedback.

It will be understood that the lead 1010 for deep brain stimulation caninclude stimulation electrodes, recording electrodes, or both. In atleast some embodiments, the lead is rotatable so that the stimulationelectrodes can be aligned with the target neurons after the neurons havebeen located using the recording electrodes.

Stimulation electrodes may be disposed on the circumference of the leadto stimulate the target neurons. Stimulation electrodes may bering-shaped so that current projects from each electrode equally inevery direction at any given length along the axis of the lead. Toachieve current steering, segmented electrodes can be utilizedadditionally or alternatively. Though the following descriptiondiscusses stimulation electrodes, it will be understood that allconfigurations of the stimulation electrodes discussed may be utilizedin arranging recording electrodes as well.

FIG. 1A illustrates one embodiment of a lead 100. The device includes alead body 110, one or more ring electrodes 120, and a plurality ofsegmented electrodes 130. The lead body 110 can be formed of abiocompatible, non-conducting material such as, for example, a polymericmaterial. Suitable polymeric materials include, but are not limited to,silicone, polyethylene, polyurethanes, polyureas, or polyurethane-ureas.In at least some instances, the lead may be in contact with body tissuefor extended periods of time. In at least some embodiments, the lead hasa cross-sectional diameter of no more than 1.5 mm and may be in therange of 0.75 to 1.5 mm. In at least some embodiments, the lead has alength of at least 10 cm and the length of the lead may be in the rangeof 25 to 70 cm.

Stimulation electrodes may be disposed on the lead body 110. Thesestimulation electrodes may be made using a metal, alloy, conductiveoxide, or any other suitable conductive material. Examples of suitablematerials include, but are not limited to, platinum, iridium, platinumiridium alloy, stainless steel, titanium, or tungsten. Preferably, thestimulation electrodes are made of a material that is biocompatible anddoes not substantially corrode under expected operating conditions inthe operating environment for the expected duration of use.

In at least some embodiments, any of the electrodes can be used as ananode or cathode and carry anodic or cathodic current. In someinstances, an electrode might be an anode for a period of time and acathode for a period of time. In other embodiments, the identity of aparticular electrode or electrodes as an anode or cathode might befixed.

The lead contains a plurality of segmented electrodes 130. Any number ofsegmented electrodes 130 may be disposed on the lead body 110. In someembodiments, the segmented electrodes 130 are grouped in sets ofsegmented electrodes, each set disposed around the circumference of thelead at or near a particular longitudinal position. The lead may haveany number of sets of segmented electrodes. In at least someembodiments, the lead has one, two, three, four, five, six, seven, oreight sets of segmented electrodes. In at least some embodiments, eachset of segmented electrodes contains the same number of segmentedelectrodes 130. In some embodiments, each set of segmented electrodescontains three segmented electrodes 130. In at least some otherembodiments, each set of segmented electrodes contains two, four, five,six, seven or eight segmented electrodes. The segmented electrodes 130may vary in size and shape. For example, in FIG. 1B, the segmentedelectrodes 130 are shown as portions of a ring or curved rectangularportions. In some other embodiments, the segmented electrodes 130 arecurved square portions. The shape of the segmented electrodes 130 mayalso be substantially triangular, diamond-shaped, oval, circular orspherical. In some embodiments, the segmented electrodes 130 are all ofthe same size, shape, diameter, width or area or any combinationthereof. In some embodiments, the segmented electrodes of each set (oreven all segmented electrodes) may be identical in size and shape.

In at least some embodiments, each set of segmented electrodes 130 maybe disposed around the circumference of the lead body 110 to form asubstantially or approximately cylindrical shape around the lead body110. The spacing of the segmented electrodes 130 around thecircumference of the lead body 110 may vary. In at least someembodiments, equal spaces, gaps or cutouts are disposed between eachsegmented electrodes 130 around the circumference of the lead body 110.In other embodiments, the spaces, gaps or cutouts between segmentedelectrodes may differ in size or shape. In other embodiments, thespaces, gaps, or cutouts between segmented electrodes may be uniform fora particular set of segmented electrodes or for all sets of segmentedelectrodes. The segmented electrodes 130 may be positioned in irregularor regular intervals around the lead body 110.

Stimulation electrodes in the form of ring electrodes 120 may bedisposed on any part of the lead body 110, usually near a distal end ofthe lead. FIG. 1A illustrates a portion of a lead having one ringelectrode. Any number of ring electrodes may be disposed along thelength of the lead body 110. For example, the lead body may have onering electrode, two ring electrodes, three ring electrodes or four ringelectrodes. In some embodiments, the lead will have five, six, seven oreight ring electrodes. Other embodiments do not include ring electrodes.

In some embodiments, the ring electrodes 120 are substantiallycylindrical and wrap around the entire circumference of the lead body110. In some embodiments, the outer diameter of the ring electrodes 120is substantially equal to the outer diameter of the lead body 110.Furthermore, the width of ring electrodes 120 may vary according to thedesired treatment and the location of the target neurons. In someembodiments the width of the ring electrode 120 is less than or equal tothe diameter of the ring electrode 120. In other embodiments, the widthof the ring electrode 120 is greater than the diameter of the ringelectrode 120.

Conductors (not shown) that attach to or from the ring electrodes 120and segmented electrodes 130 also pass through the lead body 110. Theseconductors may pass through the material of the lead or through a lumendefined by the lead. The conductors are presented at a connector forcoupling of the electrodes to a control unit (not shown). In oneembodiment, the stimulation electrodes correspond to wire conductorsthat extend out of the lead body 110 and are then trimmed or ground downflush with the lead surface. The conductors may be coupled to a controlunit to provide stimulation signals, often in the form of pulses, to thestimulation electrodes.

FIG. 1B is a schematic perspective view of another embodiment of a leadhaving a plurality of segmented electrodes. As seen in FIG. 1B, theplurality of segmented electrodes 130 may be arranged in differentorientations relative to each other. In contrast to FIG. 1A, where thethree sets of segmented electrodes are aligned along the length of thelead body 110, FIG. 1B displays another embodiment in which the threesets of segmented electrodes 130 are staggered. In at least someembodiments, the sets of segmented electrodes are staggered such that nosegmented electrodes are aligned along the length of the lead body 110.In some embodiments, the segmented electrodes may be staggered so thatat least one of the segmented electrodes is aligned with anothersegmented electrode of a different set, and the other segmentedelectrodes are not aligned.

Any number of segmented electrodes 130 may be disposed on the lead body110 in any number of sets. FIGS. 1A and 1B illustrate embodimentsincluding three sets of segmented electrodes. These three sets ofsegmented electrodes 130 may be disposed in different configurations.For example, three sets of segmented electrodes 130 may be disposed onthe distal end of the lead body 110, distal to a ring electrode 120.Alternatively, three sets of segmented electrodes 130 may be disposedproximal to a ring electrode 120. By varying the location of thesegmented electrodes 130, different coverage of the target neurons maybe selected. For example, a specific configuration may be useful if thephysician anticipates that the neural target will be closer to thedistal tip of the lead body 110, while another arrangement may be usefulif the physician anticipates that the neural target will be closer tothe proximal end of the lead body 110. In at least some embodiments, thering electrodes 120 alternate with sets of segmented electrodes 130.

Any combination of ring electrodes 120 and segmented electrodes 130 maybe disposed on the lead. In some embodiments the segmented electrodesare arranged in sets. For example, a lead may include a first ringelectrode 120, two sets of segmented electrodes, each set formed ofthree segmented electrodes 130, and a final ring electrode 120 at theend of the lead. This configuration may simply be referred to as a1-3-3-1 configuration. It may be useful to refer to the electrodes withthis shorthand notation. Other eight electrode configurations include,for example, a 2-2-2-2 configuration, where four sets of segmentedelectrodes are disposed on the lead, and a 4-4 configuration, where twosets of segmented electrodes, each having four segmented electrodes 130are disposed on the lead. In some embodiments, the lead will have 16electrodes. Possible configurations for a 16-electrode lead include, butare not limited to 4-4-4-4, 8-8, 3-3-3-3-3-1 (and all rearrangements ofthis configuration), and 2-2-2-2-2-2-2-2.

FIG. 2 is a schematic diagram to illustrate radial current steeringalong various electrode levels along the length of a lead. Whileconventional lead configurations with ring electrodes are only able tosteer current along the length of the lead (the z-axis), the segmentedelectrode configuration is capable of steering current in the x-axis,y-axis as well as the z-axis. Thus, the centroid of stimulation may besteered in any direction in the three-dimensional space surrounding thelead body 110. In some embodiments, the radial distance, r, and theangle θ around the circumference of the lead body 110 may be dictated bythe percentage of anodic current (recognizing that stimulationpredominantly occurs near the cathode, although strong anodes may causestimulation as well) introduced to each electrode as will be describedin greater detail below. In at least some embodiments, the configurationof anodes and cathodes along the segmented electrodes 130 allows thecentroid of stimulation to be shifted to a variety of differentlocations along the lead body 110.

As can be appreciated from FIG. 2, the centroid of stimulation can beshifted at each level along the length of the lead. The use of multiplesets of segmented electrodes 130 at different levels along the length ofthe lead allows for three-dimensional current steering. In someembodiments, the sets of segmented electrodes 130 are shiftedcollectively (i.e. the centroid of simulation is similar at each levelalong the length of the lead). In at least some other embodiments, eachset of segmented electrodes 130 is controlled independently. Each set ofsegmented electrodes may contain two, three, four, five, six, seven,eight or more segmented electrodes. It will be understood that differentstimulation profiles may be produced by varying the number of segmentedelectrodes at each level. For example, when each set of segmentedelectrodes includes only two segmented electrodes, uniformly distributedgaps (inability to stimulate selectively) may be formed in thestimulation profile. In some embodiments, at least three segmentedelectrodes 130 are utilized to allow for true 360° selectivity.

In addition to 360° selectivity, a lead having segmented electrodes mayprovide several advantages. First, the lead may provide for moredirected stimulation, as well as less “wasted” stimulation (i.e.stimulation of regions other than the target region). By directingstimulation toward the target tissue, side effects may be reduced.Furthermore, because stimulation is directed toward the target site, thebattery in an implantable pulse generator may last for a longer periodof time between recharging.

As previously indicated, the foregoing configurations may also be usedwhile utilizing recording electrodes. In some embodiments, measurementdevices coupled to the muscles or other tissues stimulated by the targetneurons or a unit responsive to the patient or clinician can be coupledto the control unit or microdrive motor system. The measurement device,user, or clinician can indicate a response by the target muscles orother tissues to the stimulation or recording electrodes to furtheridentify the target neurons and facilitate positioning of thestimulation electrodes. For example, if the target neurons are directedto a muscle experiencing tremors, a measurement device can be used toobserve the muscle and indicate changes in tremor frequency or amplitudein response to stimulation of neurons. Alternatively, the patient orclinician may observe the muscle and provide feedback.

Radially segmented electrode arrays may be manufactured in a variety ofways. In at least some embodiments, concentric cylindrical electrodeshaving windowed portions may be used to form a radially segmentedelectrode array. The plurality of cylindrical electrodes may be modifiedto utilize different numbers of electrodes, to adjust the radial spacingbetween electrodes or to vary the longitudinal position between levelsof electrodes.

FIG. 3A is a schematic perspective view of one embodiment of an innercylinder 300. As will be explained further below, the shape and size ofthe inner cylinder 300 may be modified. Furthermore, the inner cylinder300 may be formed from a metal, alloy, conductive oxide, or any othersuitable conductive material. In some embodiments, the inner cylinder300 is formed of platinum, platinum-iridium, iridium, 316L stainlesssteel, tantalum, nitinol or a conductive polymer. As seen in FIG. 3A,the inner cylinder 300 may include an inner window 310. The size andshape of the inner window 310 of the inner cylinder 300 may also bemodified.

The inner cylinder 300 may also include an inner window 310. FIG. 3Aillustrates one embodiment of an inner window 310 that is cut from theinner cylinder 300. As seen in FIG. 3A, the inner window 310 of theinner cylinder 310 may be formed of a rectangular section that is cutfrom the inner cylinder 310 about the circumference. It will beunderstood that the size and shape of the inner window 310 may vary. Forexample, in some embodiments, the inner window 310 may be formed in theshape of a square. Alternatively, the inner window 310 may be formedsuch that the width about the circumference of the inner cylinder 300 islonger or shorter than the length of the inner window 310. The innerwindow 310 may also be formed of different shapes. For example, theinner window 310 may be formed of a square, a triangle, a circle or adiamond.

The inner cylinder 300 may also include more than one inner window 310.For example, in some embodiments, two inner windows 310 may be formed inthe inner cylinder 300. It will be understood that any number of innerwindows 310 may be formed in the inner cylinder 300 (e.g. two, there,four, five, six, seven, eight, ten or twelve windows.) These innerwindows 310 may be disposed at regular intervals about the circumferenceof the inner cylinder 300. In some embodiments, each of the innerwindows 310 of the inner cylinder 300 is formed in a different shape.Alternatively, in some embodiments, the inner windows 310 are formed ofthe same shape and size.

FIG. 3B is a schematic perspective view of the inner cylinder 300 ofFIG. 3A after formation of an inner window 310. The inner window 310 maybe formed in the inner cylinder 300 through any suitable method. Forexample, an inner window 310 may be laser cut through the inner cylinder300. As seen in FIG. 3B, the resulting structure is an inner cylinder300 having an inner window 310 that extends along half the circumferenceof the inner cylinder 300. Furthermore, the inner window 310 may be cutso that ring portions 320 remain along the top and bottom of thecylinder. The ring portions 320 may be useful in coupling the innercylinder 300 onto the lead 100. It will be understood that the ringportions 320 may be of any suitable size or thickness, depending on thedesired size of the inner window 310.

FIG. 4A is a schematic perspective view of one embodiment of an outercylinder 400. The outer cylinder 400 may be formed of any suitableconductive material, such as those described above with respect to theinner cylinder 300. In some embodiments, the outer cylinder 400 and theinner cylinder 300 are formed of the same conductive material. In atleast some other embodiments, the outer cylinder 400 and the innercylinder 300 are formed of different conductive materials.

The outer cylinder 400 may also be formed in different shapes and sizes.For example, the length of the outer cylinder 400 may be increased ordecreased as desired. In at least some embodiments, the length of theouter cylinder 400 is the same as the length of the inner cylinder 300.Alternatively, the outer cylinder 400 may be shorter or longer than theinner cylinder 300. The diameter of the outer cylinder 400 may also bemodified. For example, the inner diameter of the outer cylinder 400 maycorrespond to the outer diameter of the inner cylinder 300. In someembodiments, the inner diameter of the outer cylinder 400 is slightlylarger than the outer diameter of the inner cylinder 300. It may bedesirable to form an isodiametric lead. In some embodiments, the outerdiameter of the outer cylinder 400 corresponds to the diameter of thelead body.

The outer cylinder 400 may also include an outer window 410. The outerwindow 410 may be formed in an suitable shape and size as described withreference to the inner window 310 of the inner cylinder 300. In someembodiments, the outer window 410 is formed in the same shape as that ofthe inner window 310. In some embodiments, the outer window 410 isformed in a shape that is complementary to the shape of the uncutportion of the inner cylinder 300. The outer cylinder 400 may alsoinclude more than one outer window 410. For example, in someembodiments, two, three, four, five, six, seven, eight, ten or twelveouter windows 410 may be formed in the outer cylinder 400. The number ofouter windows 410 formed may correspond to the number of uncut portionsremaining on the inner cylinder 300 after the inner windows 310 havebeen formed.

The outer windows 410 may be cut so that ring portions 420 remain alongthe top and bottom of the outer cylinder 400. The ring portions 420 maybe useful in coupling the outer cylinder 400 to the inner cylinder 300and the lead body 110. It will be understood that the ring portions 420may be of any suitable size or thickness, depending on the desired sizeof the outer window 410. In some embodiments, the ring portions 420 areof the same shape and size as those of the inner cylinder 300. The ringportions 420 and the outer window 410 may be formed by laser cutting aportion of the outer cylinder 400 as described above. FIG. 4B is aschematic perspective view of the outer cylinder of FIG. 4A afterformation of a window.

In some embodiments, the inner cylinder 300 and the outer cylinder 400may be coupled to one another to form a cylinder assembly. For example,the inner cylinder 300 may be disposed within the outer cylinder 400. Insome embodiments, the inner cylinder 300 is slid into the outer cylinder400 and the two are secured using any suitable methods. The manufacture,arrangement and configuration of the cylinder assembly will be morethoroughly discussed with reference to FIGS. 5-7.

FIG. 5 is a schematic cross-sectional view of one embodiment of acylinder assembly 500 having an inner cylinder 300, an outer cylinder400 and an insulator 510. As seen in FIG. 5, the inner diameter of theouter cylinder 400 is slightly larger than the outer diameter of theinner cylinder 300. Furthermore, an insulator 510 may be applied to theinner cylinder 300, the outer cylinder 400 or both, to electricallyinsulate them from one another.

The insulator 510 may include any suitable insulator such as, forexample, silicone, suitable fluoropolymers, polyurethane, PEEK,polysulfone, nylon, Teflon®, thermoplastics, other liquid crystalpolymers or some other implant grade non-conductive material. It will beunderstood that the insulators listed above are given by way of exampleand that any suitable insulator may be used. In some embodiments, theinsulator 510 includes a thin cylinder of insulative material.Furthermore, the insulator 510 may be formed of any combination of thematerials described above. In the case of silicone and certain otherinsulators, the insulator 510 may be applied using a dip coatingtechnique. The insulator 510 may be useful may be useful in electricallyseparating two adjacent cylinders.

In some embodiments, the insulator 510 covers the entirety or asubstantial portion of the outer diameter of the inner cylinder 300.Additionally, the insulator 510 may be applied to the inner diameter ofthe outer cylinder 400. Thus, the insulator 510 may applied to either ofthe cylinders. In at least some other embodiments, the insulator 510 isapplied to both the inner cylinder 300 and the outer cylinder 400. Thus,by using an insulator 510, a cylinder assembly may be formed having twoportions, each portion corresponding to one of the cylinders and beingconfigured to function independently of the other.

FIG. 6 is a schematic perspective view of an inner cylinder 300 disposedwithin the outer cylinder 400. As seen in FIG. 6, the inner cylinder 300may be fully housed within the outer cylinder 400. In some embodiments,the inner cylinder 300 and the outer cylinder 400 are concentric. Theinner cylinder 300 and the outer cylinder 400 may also be arranged suchthat the cylinders are aligned longitudinally. Furthermore, the innerwindow 310 and the outer window 410 may be aligned in a variety ofarrangements. In some embodiments, the inner cylinder 300 and the outercylinder 400 are aligned such that a portion of the inner cylinder 300is exposed through the outer window 410 of the outer cylinder 400.

The inner cylinder 300 and the outer cylinder 400 may be coupledtogether using a variety of methods. For example, in some embodiments,the outer cylinder 400 is crimped down on the inner cylinder 300 atvarious locations to create a mechanical connection between the twocylinders. The crimped portions 610 may be disposed around thecircumference of the ring portions 320 and 420. In some embodiments, thecrimped portions 610 are disposed at one end of the two cylinders. Asshown in FIG. 6, the crimped portions 610 may also be disposed at bothends at various intervals along the circumference of the ring portions.In at least some other embodiments, a swaging process is used to securethe inner cylinder 300 to the outer cylinder 400. It will be understoodthat any method of securing the two cylinders can be used to create thecylinder assembly. For example, instead of mechanically deforming thetwo cylinders, a suitable biocompatible adhesive may be used to couplethe two cylinders.

An insulator 510 may be applied to the cylinder assembly 500. Theinsulator 510 may be any one of or a combination of the insulatorsdisposed between the inner cylinder 300 and the outer cylinder 400. Insome embodiments, the entire cylinder assembly 500 is coated with aninsulator 510 and portions of the insulator 510 are removed from areasthat will be used as electrodes. For example, if circular electrodes aredesired, an insulator 510 may be used to cover the entire cylinderassembly 500 and a circular portion of the insulator 510 may be removedfrom the outside surface of the outer cylinder. Any method of removingthe undesired insulator 510 may be used. In some embodiments, laserablation is used to remove the insulator 510 from the surface of thecylinders in the shape of the desired electrodes.

FIG. 7 is a schematic cross-sectional view of one embodiment of acylinder assembly 500 showing the location of the inner window and theouter window. It will be understood that the inner cylinder 300 may berotated within the outer cylinder 400 in a plurality of arrangementsprior to coupling the two. Thus, in some embodiments, the outer window410 is aligned with an uncut portion of the inner cylinder 300 so thatthe inner cylinder 300 is capable of stimulating tissue through theouter window 400. In embodiments where the cylinders are used asrecording electrodes, the inner cylinder 300 may likewise be alignedwith the outer windows 410 to achieve proper measurement of anelectrical signal. The inner window 310 of the inner cylinder 300 andthe outer window 410 of the outer cylinder 400 may be aligned such thatno portions of the cylinders overlap except for the ring portions 320and 420. Thus, the inner window 310 may be completely aligned with theuncut portion of the outer cylinder 400 and the outer window 410 may becompletely aligned with the uncut portion of the inner cylinder 300. Itwill be understood that in at least some other embodiments, the uncutportions of the inner cylinder 300 and outer cylinder 400 at leastpartially overlap. Furthermore, in embodiments having multiple innerwindows 310 and/or multiple outer windows 410, a combination ofoverlapping and non-overlapping portions may be formed with twocylinders.

Conductors 810 may be attached to any portion of the inner cylinder 310and/or outer cylinder 410. For example, conductors may be attached tothe uncut portions of the cylinders or to the ring portions of thecylinders. FIG. 8 is a schematic perspective view of a cylinder assembly500 coupled to a plurality of conductors 810. The outer cylinder 400 iscrimped down onto the inner cylinder 300 at crimped portions 610. Asseen in FIG. 8, the conductors may extend through and disposed insidethe two cylinders. Thus, in some embodiments, a piece of the insulator510 may be removed so that that conductor 810 can properly attach to oneof the cylinders. Any method of removing a fragment of the insulator 510may be used. In some embodiments, an ablation process is used to removepieces of the insulator 510 so that conductors 810 may be attached tothe cylinders. In some embodiments, the conductors 810 are laser weldedto the inner cylinder 300 and outer cylinder 400.

Any number of conductors 810 may be coupled to the cylinders. In someembodiments, each cylinder is coupled to a designated conductor 810. Inat least some other embodiments, multiple conductors 810 are coupled toeach of the cylinders. The same or a different number of conductors 810may be coupled to each of the cylinders. Thus, in this manner thecylinder assembly 500 may be formed to have two or more independentelectrodes composed of the inner and outer cylinders.

It will be understood that as explained, in some embodiments, the outercylinder 400 forms one set of one or more electrodes and the innercylinder 300 forms another set of electrodes. The set of electrodesdisposed on the inner cylinder 300 may be recessed because of theirradial positioning with respect to the outer cylinder 400.

In some embodiments, it may be desirable to create a lead 100 that isisodiametric. An elevating plate 910 disposed on a portion of the innercylinder within the outer window 410 of the outer cylinder 400 may beused to form such a lead. FIG. 9 is a schematic perspective view of acylinder assembly 500 having an elevating plate 910, the cylinderassembly 500 being coupled to a plurality of conductors 810. Though FIG.9 illustrates an elevating plate 910 in the shape of a curved member, itwill be understood that a variety of shapes and sizes may be used toform the elevating plate 910. In some embodiments, the shape of theelevating plate 910 corresponds to the outer window 410 of the outercylinder 400.

As seen in FIG. 9, the elevating plate 910 may be electrically coupledto the inner cylinder 300. In some embodiments, conductors 810 aredirectly coupled to the elevating plate 910. The elevating plate 910 maybe adhered or welded to the inner cylinder 300 through any suitablemethod. In some embodiments, the elevating plate 910 is unitarily formedwith the inner cylinder 300 so that the inner cylinder 300 comprises araised portion that will fit within the outer window 410 of the outercylinder 400. In order to electrically insulate the elevating plate 910from the outer cylinder 400, the sides of the elevating plate 910 may becoated with an insulator 510. In some embodiments, the entire elevatingplate 910 is coated with an insulator 510 and portions of the insulator510 are removed as desired (e.g. to couple the elevating plate 910 toconductors or to create electrodes in a desired shape as describedabove).

FIG. 10A is a schematic perspective view of one embodiment of a portionof a lead having a plurality of cylinder assemblies 500 and spacers 950.As seen in FIG. 10A, spacers 950 may be used to control the distancebetween the cylinder assemblies 500 and to electrically insulate onecylinder assembly 500 from another. Each spacer 950 may be in the formof a short cylinder or ring that separates the two cylinder assemblies500 as illustrated in FIG. 10A. The spacers 950 may be formed of anysuitable non-conductive material capable of electrically insulating thestimulating portions of the cylinder assemblies 500. It will beunderstood that the size and shape of the spacers 950 may be varied toseparate the cylinder assemblies 500 as desired. For example, in someembodiments, the spacers 950 have the same longitudinal length as thecylinder assemblies 500. Alternatively, the spacers 950 may be shorteror longer in the longitudinal direction than the cylinder assemblies500. The spacers 950 may also have the same outer diameter as thecylinder assemblies 500 in order to produce an isodiametric lead.

One of ordinary skill in the art will readily appreciate that astaggered lead arrangement may be formed using the cylinder assemblies500 described above. FIG. 10B is a schematic perspective view of anotherembodiment of a portion of a lead having a plurality of cylinderassemblies 500 arranged in a staggered orientation. As seen in FIG. 10B,by rotating the cylinder assemblies 500 about the circumference of thelead body 110, a staggered lead arrangement may be formed. In someembodiments, the cylinder assemblies 500 are arranged such thatsuccessive cylinder assemblies 500 are staggered by 30, 45, 60, 90 or120 degrees.

Modifications of these methods are possible. In some embodiments,multiple inner cylinders 300 may be disposed within the outer cylinder400. For example, as seen in FIG. 12, a cylinder assembly 500 may beformed of a first inner cylinder 300 housed within a second innercylinder 300, both of which are housed within an outer cylinder 400. Thethree cylinders may be concentric. Furthermore, windows may be formed ineach of the cylinders and aligned as desired. Thus, using thistechnique, a cylinder assembly 500 may be formed having two, three,four, five, six, seven, eight, ten or twelve cylinders, each beinginsulated from the others using an insulator 510 such that each cylinderis able to stimulate the surrounding tissue with an independent set ofparameters. For example, the frequency of stimulation of the firstcylinder may be different than that of the second and third cylinders.Multiple conductors 810 may be disposed within the cylinders, eachcylinder being coupled to a designated conductor 810. Furthermore,multiple elevating plates 910 may be used to form an isodiametric lead.Thus, by varying the number, size and shape of inner cylinders 300, itmay be possible to produce leads having different stimulation andrecording advantages. In some embodiments, these methods are used withlead constructions other than deep brain stimulation leads.

The above specification, examples and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed as new and desired to be protected by U.S. LettersPatent:
 1. A lead for electrical stimulation, the lead comprising: alead body having a distal end section; a plurality of cylinderassemblies disposed along the distal end section of the lead body, eachcylinder assembly comprising at least one inner conductive cylinder, anouter conductive cylinder with at least one outer window cut out fromthe outer cylinder, the outer cylinder being secured to and disposedconcentric to the at least one inner cylinder with a portion of each ofthe at least one inner cylinder aligned with the at least one outerwindow of the outer cylinder, and at least one insulator configured andarranged to electrically insulate each of the at least one innercylinder and the outer cylinder; and a plurality of conductors extendingalong the lead body and electrically coupled to the inner and outerconductive cylinders of the plurality of cylinder assemblies.
 2. Thelead of claim 1, wherein the outer cylinder and a one of the at leastone inner cylinder are crimped together.
 3. The lead of claim 1, whereinthe outer cylinder and a one of the at least one inner cylinder areswaged.
 4. The lead of claim 1, wherein at least one of the at least oneinner cylinders has an inner window.
 5. The lead of claim 4, wherein atleast one of the at least one outer window of the outer cylinder isdisposed on an opposite side of the lead body from the inner window of aone of the at least one inner cylinders.
 6. The lead of claim 4, whereinat least one of the at least one outer window of the outer cylinder doesnot overlap with the inner window of a one of the at least one innercylinders.
 7. The lead of claim 1, further comprising at least oneconductive elevating member disposed within the outer window andelectrically coupled to a one of the at least one inner cylinder, theelevating member being arranged as isodiametric with the outer cylinder.8. The lead of claim 1, wherein the at least one inner cylinder isexactly two concentric inner cylinders.
 9. The lead of claim 8, whereinthe at least one insulator comprises i) a first insulator disposedbetween the outer cylinder and a one of the two concentric innercylinders and ii) a second insulator disposed between the two concentricinner cylinders.
 10. The lead of claim 1, wherein that at least oneinner cylinder is a single inner cylinder and wherein the at least oneinsulator is a single insulator disposed between the outer cylinder andthe single inner cylinder.
 11. The lead of claim 1, wherein theplurality of cylinder assemblies are disposed at spaced-apartlongitudinal levels along the length of the lead.
 12. The lead of claim1, further comprising a spacer disposed between two of the plurality ofcylinder assemblies.
 13. An implantable stimulation system, comprising:the lead of claim 1; and a control module coupleable to the lead. 14.The implantable stimulation system of claim 13, wherein the implantablestimulation device is a deep brain stimulator.
 15. A lead for electricalstimulation, the lead comprising: a lead body having a distal endsection; at least one electrode assembly disposed along the distal endsection of the lead body, each electrode assembly comprising a firstelectrode comprising a conductive outer cylinder with at least one outerwindow cut out from the outer cylinder, a second electrode comprising aconductive first inner cylinder disposed concentrically within the outercylinder, wherein a portion of the first inner cylinder is aligned withthe at least one outer window of the outer cylinder, and a firstinsulator disposed between the outer cylinder and the first innercylinder; and a plurality of conductors extending along the lead bodyand electrically coupled to the first and second electrodes of the atleast one electrode assembly.
 16. The lead of claim 15, wherein thefirst inner cylinder and the outer cylinder are crimped together. 17.The device of claim 15, wherein the first inner cylinder and the outercylinder are swaged.
 18. The device of claim 15, wherein at least one ofthe at least one electrode assembly further comprises i) a thirdelectrode comprising a conductive second inner cylinder disposedconcentrically within the first inner cylinder and ii) a secondinsulator disposed between the first inner cylinder and the second innercylinder, wherein the first inner cylinder has at least one inner windowcut out from the first inner cylinder and a portion of the second innercylinder is aligned with both the at least one outer window of the outercylinder and the at least one inner window of the first inner cylinder.19. An implantable stimulation system, comprising: the lead of claim 15;and a control module coupleable to the lead.
 20. A method ofmanufacturing a lead, the method comprising: i) forming a lead bodyhaving a distal end section; ii) disposing a plurality of cylinderassemblies along the distal end section of the lead body, each cylinderassembly comprising at least one inner conductive cylinder, an outerconductive cylinder with at least one outer window cut out from theouter cylinder, the outer cylinder being secured to and disposedconcentric to the at least one inner cylinder with a portion of each ofthe at least one inner cylinder aligned with the at least one outerwindow of the outer cylinder, and at least one insulator configured andarranged to electrically insulate each of the at least one innercylinder and the outer cylinder; and iii) coupling a plurality ofconductors to the plurality of conductor assemblies with each of theouter cylinder and the at least one inner cylinder of each of theconductor assemblies being coupled to at least one of the plurality ofconductors.